Need help with Dedicated music server.

Blindjim - I believe the HiFace is bit perfect with MC 14 on Windows 7 using WASAPI. M2Tech is still working out issues with the driver and the latest one does not work correctly, but there is an earlier beta version that provides WASAPI support in exclusive mode. Hopefully M2Tech will provide a new version soon. You do not need MC 15 to do this.

Anything that uses S/PDIF will not perform as well as asynchronous USB. With S/PDIF the target end still has to recover the clocking from the data stream. Cabling and termination on the target end will still come into play regardless of how good the clocking is on the source end.

Asynchronous USB DACs aren't cheap, so I can see interest in other solutions.

Asynchronous USB DAC's do a great job of lowering jitter from the USB. They do this by basically controlling the clocking of the signal. Many DACs use re-clocking techniques on S/PDIF signals. So, if the USB to S/PDIF interface delivers bit perfect data to such a DAC, it seems that re-clocking in the DAC should be able to produce jitter similar to that on the various asyncrhonous USB DACs. The OP's Berkeley DAC is a high end DAC which, according to the Berkeley website has "Advanced input signal jitter rejection". So, it is quite possible that a S/PDIF or maybe a AES output from a PC coupled with the Berkeley DAC may be able to produce jitter figures as good as the aysnchronous DACs. The Berkeley DAC gets great reviews both in terms of sound and in terms of features.

Chuck/Johnny - you might want to check of the system that Goodwin's High End has put together to drive the Berkeley DAC. It uses solid states disks, has no fans and uses other means to make for a really quiet system. Last I knew it was only using XP and a 16 bit (not 24 bit) Lynx card but they may have updated it. I am not necessarily recommending that system, but it is interesting to look at what they did.

I have NEVER EVER had a USB dac which is capable of USB and SPDIF sound better using the USB connection regardless of the science for why it should. All of my listening has always favored the SPDIF connection. I now use a HiFace with my MSB Power Dac and the SPDIF is far superior to going in via USB direct. I have tried different USB cables... but in the end I will stick with SPDIF, heck even TOS out of my mac mini (glass toslink cable) has beat all the USB dacs I have tried SIm Audio 300D/MSB Power Dac and too many others. Blanket statements are rarely ever true. I would never say that all SPDIF connections are inherently better than USB, but I have not yet experienced the direct USB connection that is better. NOW the HiFACE USB to SPDIF converter... that thing is AWESOME and is my main connection to my MSB DAC. It sounds better than wonderful :)